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QS9000. Ppk in QS9000 means Preliminary Process Capability Index. It should be calculated before Mass Production and based on limited product quantity. Normally, it should be more than because it39。s a short term process capability which doesn39。t consider the long term variation. But, in QS9000 3rd edition, there39。s no Compulsory Requirement that the Ppk must be more than . In QS9000 3rd edition, it states like Ppk/Cpk =.Another one is in 6Sigma. Ppk in 6Sigma means Process Performance Index. It39。s a long term process capability covered the long term process variation and based on more product quantity. Generally, in 6Sigma, the Ppk value is less than Cpk value.Ppk:Overall performance capability of a process, see 。Cp:A widely used capability index for process capability studies. It may range in value from zero to infinity with a larger value indicating a more capable process. Six Sigma represents Cp of . 在流程能力分析方面被廣泛應(yīng)用的能力指數(shù),在數(shù)值方面它可能是從零到顯示更強有力流程的無窮大之間的某個點。六個西格瑪代表的是Cp=。 Cpk:A process capability index bining Cp and k (difference between the process mean and the specification mean) to determine whether the process will produce units within tolerance. Cpk is always less than or equal to (表示流程平均值與上下限區(qū)間平均值之間的差異)結(jié)合起來的流程能力指數(shù),它用來確定流程是否將在容忍度范圍內(nèi)生產(chǎn)產(chǎn)品,Cpk通常要么比Cp值小,要么與Cp值相同?!痹谝话愕腝S9000或TS16949推行過程中,Ppk用來表示短期能力指數(shù),Cpk用來表示長期能力指數(shù)。但是受知識所限,我本人沒有看到這方面的權(quán)威資料。這位網(wǎng)友的帖子上面也表達(dá)了兩種不同的觀點,而且這兩種觀點近乎對立。我本人認(rèn)為,從Ppk的計算公式中使用的 分析,Ppk表達(dá)的應(yīng)該是一個包含引起變差的普通原因和特殊原因的過程。這樣的過程其實就是一個非受控過程,而一個非受控過程在理論上應(yīng)該是在過程初期和長期過程中都會遇到的。、,采用連續(xù)抽樣。轉(zhuǎn)載請注明出自六西格瑪品質(zhì)論壇 ,本貼地址:頁: [1] 1. 若不給自己設(shè)限,則人生中就沒有限制你發(fā)揮的藩籬。2. 若不是心寬似海,哪有人生風(fēng)平浪靜。在紛雜的塵世里,為自己留下一片純靜的心靈空間,不管是潮起潮落,也不管是陰晴圓缺,你都可以免去浮躁,義無反顧,勇往直前,輕松自如地走好人生路上的每一步3. 花一些時間,總會看清一些事。用一些事情,總會看清一些人。有時候覺得自己像個神經(jīng)病。既糾結(jié)了自己,又打擾了別人。努力過后,才知道許多事情,堅持堅持,就過來了。4. 歲月是無情的,假如你丟給它的是一片空白,它還給你的也是一片空白。歲月是有情的,假如你奉獻(xiàn)給她的是一些色彩,它奉獻(xiàn)給你的也是一些色彩。你必須努力,當(dāng)有一天驀然回首時,你的回憶里才會多一些色彩斑斕,少一些蒼白無力。只有你自己才能把歲月描畫成一幅難以忘懷的人生畫卷。學(xué)習(xí)